Occluding device implantation by open-heart surgery has historically been used to treat cardiac defects or tissue openings. More recently, to avoid the trauma and complications associated with open-heart surgery, a variety of trans-catheter closure techniques have been developed. In such techniques, an occluding device is delivered through a catheter to the site of the opening or defect, where it is deployed.
A variety of trans-catheter-delivered devices are known, including devices that require assembly at the site of the tissue opening or require threading or “buttoning” of discrete device elements. Other devices include self-expanding devices. An example of a self-expanding device includes an occlusion bag, a tube, a guide catheter, a super elastic wire, a release mechanism, and a delivery sheath. The super elastic wire is attached to the release mechanism and the wire, and the release mechanism, occlusion bag, guide catheter and tube are inserted into the delivery sheath for transport to an aperture. After delivery, the occlusion bag is placed within the aperture and the wire is deployed within the bag. The bag and wire are repositioned, if necessary, and the release mechanism is activated to release the wire.
Another example of a self-expanding device includes a shape-set tubular metal fabric device and, optionally, an occluding fiber included in the hollow portions of the device. The metal fabric defines a medical device shaped like a bell, which can be collapsed for passage through a catheter for deployment in a channel of a patient's body.
Most trans-catheter delivery devices are deployed using one of two basic techniques: pulling back an outer catheter to release the device, or pushing the device free of the catheter with a push rod. Each of these systems utilizes a handle to actuate the mechanism used to deploy the device. An example of such a system includes a flexible urging member for urging the sealing device through the catheter and a remotely located control means for advancing the urging member. In this example, the control means includes a threaded, tubular shaft connected to the urging member and a manually rotatable threaded rotor mounted on the shaft. The threads on the rotor mate with the threads on the shaft so that the rotation of the rotor through a known angle will advance the shaft and the urging member a known distance.
An example of a system that utilizes a pull back outer shaft or catheter includes a handle that may selectively hold the delivery system components at any configuration during deployment and positioning of the device. The outer catheter of such a system is pulled back to release the device by actuating a sliding lever and a rotating finger ring on the delivery system handle.